1. Field of the Invention
This invention relates generally to integrated circuits and, more particularly, to a bridge circuit preferably fabricated in N channel power metal-oxide-semiconductor (MOS) technology and to a method of fabricating an improved integrated bridge circuit.
2. Description of the Related Art
Bridge circuits of various types have been used, in the past, in a number of different electronic applications. The bridge circuit of the general type to which the present bridge circuit invention is directed is sometimes referred to as the H-bridge circuit. This class or type of circuit is suitable for general fast switching applications such as are needed in power supplies, audio amplifiers and small motor controls. It has been known in the past to implement such a class or type of bridge circuit with four discrete bipolar devices. This implementation has had the disadvantage of being relatively slow for many applications.
More recently, this class or type of bridge circuit has been implemented by four discrete power metal-oxide-semiconductor (MOS) devices assembled together on a single insulating type of substrate. However, the fabrication of this general type of bridge circuit by use of unipolar (MOS) discrete devices does not provide efficient use of space available in a semiconductor chip which is a disadvantage also shared by the four discrete bipolar device implementations.